van-picker组件default-index属性设置不生效踩坑及解决

// 1.给van-picker设置ref，如ref="van_picker"

	<van-popup v-model="showPicker" position="bottom">
		<van-picker
			show-toolbar  value-key="label"  ref="van_picker"
			:columns="columns"  :default-index="defaultBuIndex"
			@confirm="onConfirm" @cancel="showPicker = false"
		/>
	</van-popup>
	
// 2. 在需要的方法中调用：  

	 this.$nextTick(() =>{
		this.$refs.van_picker.setIndexes([0])    // 注意这里是数组[索引值]
	})

<van-picker
    :show-toolbar="true"
    :columns="reason"
    ref="picker"
    @change="change"
  />
    <div class="btn" @click="handlePopSubmit('reason')">确认</div>


change（value）{
//单列：Picker 实例，选中值，选中值对应的索引
//多列：Picker 实例，所有列选中值，当前列对应的索引
}

<van-picker
    :show-toolbar="true"
    :columns="reason"
    ref="picker"
    ref="pick"
  />
  <div class="btn" @click="handlePopSubmit('reason')">确认</div>

handlePopSubmit(){
    console.log('选中的值'，this.$refs.picker.getValues)
}

<van-picker
    :show-toolbar="true"
    :columns="reason"
    ref="picker"
    @confirm="handleReasonChange"
  />
  <div class="btn" @click="handlePopSubmit('reason')">确认</div>


handleReasonChange(value, index) {
//value ：选中的值 取值即可
//index： 下标   
  }

handlePopSubmit(){
     let pickReason = (this.$refs.picker as any).$el.children[0].children[1]; //拿到顶部栏的确认元素
      pickReason.click(); //执行一下
 }